Japan, the United States, Australia and India are finalizing a plan to hold their first face-to-face summit under the Quad grouping in Washington on Sept. 24 to discuss their ties to counter China's growing influence in the Indo-Pacific region, Japanese and U.S. diplomatic sources said Thursday.

The leaders of the four nations are also expected to raise the situation in Afghanistan, when China could recognize the interim government by the Islamist militant Taliban, which regained control of the country by force last month.

The development comes as U.S. President Joe Biden has proposed the summit in hopes of facilitating cooperation among the four countries, and as Prime Minister Yoshihide Suga seeks to assure that Tokyo's commitment to the Japan-U.S. alliance will continue after he leaves office, according to the sources.

Last week, Suga expressed his intention not to seek re-election as leader of the ruling Liberal Democratic Party when it holds its presidential election on Sept. 29. The LDP leader concurrently serves as prime minister as the party controls the House of Representatives. His term as party leader will expire on Sept. 30.

The four leaders also including Australian Prime Minister Scott Morrison and Indian Prime Minister Narendra Modi held a video conference in mid-March but a face-to-face meeting has yet to be held.

Suga is set to visit the U.S. capital from Sept. 23 to 26 but will skip attending the U.N. General Assembly to be held in New York around the same time, the sources said. He will deliver a video speech instead.